Manufacture of artificial silk thread



Feb. 11,1941. H. B. mm; m1 I 2,231,851

ummcwfis or AMIFI'QAL sxm'rnnw I Filed Jan. as, 1938 HAYDEN BKLINE AND LOUIS S FRYER mar-n81 Patented Feb. 11, 1941 UNITED STATES;

MANUFACTURE. or ARTIFICIAL SILK Hayden n. Kline and Louis S. Fryer, Lakewom-..

Ohio, assignors to Industrial Rayon Corporation, Cleveland, Ohio, a corporation or Dela ware Applicationlannary 25, 1938, Serial No. 186,800

3 (llaims. '(Cl..l8f 54) This invention relates to methods of and means for producing thread or the like of synthetic origin, particularly artificial sill; thread.

Among other things contemplated by the in- 5 vention is the operation of imparting to thread or the like of synthetic origin a predetermined, progressively increasing stretch, the introduction of the latter being begun before the thread or the like has become completely coagulated. A pre- 1o ierred embodiment oi the invention involves the stretching of the thread or the like by-means of a generally flared thread store device; for example, a irusto-conical thread-advancing reel. In consequence of the use oi such a device it is possible to effect a gentle, progressively increasing stretching of the thread or the like over a conslderable period of time during which the thread or the like gradually approaches complete coagulation, thereby providing a higher tensile 29 strength, a considerably reduced capacity for further elongation, and a much more uniform product.

This subject matter is described but notclaimed in application Serial No. 7,115. filed February 18, 1935, of which the present application is in part a continuation. I v

Although mention has been made 0! the fact that the invention may, if desired; be applied to the manufacture of viscose artificial silk thread,

it is not to be understood as limited to this field.

The invention is capable of employment in the.

manufacture of any thread-like article of synthetic origin, including artificial straw, staple fiber and multiple filament artificial silk thread produced by any oi the usual processes; e. g., the

viscose, nitrocellulose, cuprammonium and cellulose acetate processes. For convenience, the'lnvention has been illustrated and will be'hereinafter described as employed in connection with the pot-spinning system of manufacturing multiple filament viscose artificial silk thread Apparatus of a mud adapted to employment in the practice of the present invention is illustrated;

in the accompanying drawing. In such drawing, Figure i represents a front elevation of the apparatus, certain parts being shown more or less diagrammatically. Figure 2 is a corresponding sectional elevation. Rgurefl is an end elevation of the reel mmatically indicated in Figures 1 and 2. Figure 4 is a'detailedlo'ngitudinal elevation partly in section on the line H of Figure 8. 7 Inch figures, corresponding parts are identified by correspondingrei'erence characters.

In the apparatus of Figures 1 and 2, Viscbse is forced by a pump (not shown) through a candle filter 2 to suitable means for converting. the viscose into thread, the same taking the form of spinneretl through whichthe viscose is extruded into spinning bath to form the multiple fila- 5 ment thread 3. The thread 3 is withdrawn from the spinning bath 4 by a flared reel 5. The reel 5 is so constructed that it continuously accepts the thread directed to it, forms it into and positively advances it in'the form of a large number it) of closely spaced generally helical turns, and discharges it from the end thereof to a suitable collecting device which, as in the illustrated arrangement, may conveniently be av spinning pot.

The collecting device illustrated in the drawing 35 is shown conventionally as including, besides the spinning pot I, the usual funnel S, which has a reciprocatory motion with respect to the spinning pot l along the axis of rotation of the spinning P t itself. The purpose of such motion is to lay so the thread in a regular pattern, layer upon layer, as the cake builds up in the pot. The traverse mechanism for moving several tunnels in a multiple unit machine is illustrated as including a cam 59 mounted upon a shaft l1, said cam opas acting a lever I8 connected to a slide redid which in turn operates a bar 2| having arms 22 extending out to support and operate the respective funnels. I

Brief description of the reel 5, which may be tlil taken to exemplify a thread store device of the kind-to which the invention relates, will sulice for the purposes of the present application.

The reel illustrated in the drawing of the present application is of a type similar to that dlsas closed in British Patent No. 413,414, except that the illustrated reel is of cantilever construction; e. g, supported and driven only from its threadreceiving end. It comprises two reel members a and it provided respectively with sets of longi- 49 tudinally extending bars H and ii, the two sets of bars being disposed ln alternate relation with respect to each other. Each of the reel members is rigid in the sense that all of its parts are immovable with respect toeach other and with relation to the shaft on which the reel as a whole is mounted. The reel is generally irusto-conical in shape, being flared from its thread-receiving to its thread-discharge end, but may, of course,

have some other conformation. so

Member 9, referred to as the concentric member of the reel, is disposed concentrically of, fixed to, and rotates with the driving shaft I3. Mem

ber I0 is driven by bar-to-bar contact with memher 9 and is mounted upone bearing 14 carried by the stationary frame 15, the central axis of said bearing being both slightly offset from and inclined to the axis of rotation of the shaft l3. Consequently, since the member ID is mounted 5 symmetrically about the bearing H on which it rotates, its axis also is slightly offset from and inclined with reference to the axis of shaft l3, wherefore it is referred to as the eccentric mem ber,

In general, depending upon the angle of inclination between the reel members, there are from 50 to more than 100 thread turns uponthe reel, all of which are caused to advance along the periphery thereof by reason of the oflset and i5 inclined relation of the bar members. Because the diameter of the reel as a whole increases toward the discharge end, each turn of thread is progressively stretched as it advances along the reel, the same stretching effect being produced on 2% each succeeding turn of thread. The large number of turns of thread upon the reel eliminates any possible thread slip, as a result oi which-succeeding portions of the same thread are with drawn from the coagulating bath without varia- 2a tions having their origin in. this source. The reel itself may be and preferably is long enough to permit regeneration of the cellulose content of the viscose to proceed substantially to completion before the thread reaches the discharge end I so of the reel.

The coagulation of the thread 3, which, given time, will occur in and of itself, may be furthered by the application of an appropriate reagent from a suitable means such as a reagent distrib- 35 utor i8, preferably so positioned as to shower said reagent upon the successive turns as they approachthe discharge end of the reel 5. The reagent may be supplied to the distributors it by a supply pipe 23. It may be removed by a suitable drain trough 26 from which it is conducted by suitable conduits either to the sewer or to a make-up reservoir from which it may be recirculated in the event that the reagent is of a character making its re-use desirable.

Prior to the present invention, such stretching of the thread as it has been considered desirable to effect has been accomplished by the use of a plurality of godet Wheels operating at diflerent peripheral speeds. Older methods have involved the drawing of thread through a series of guides, over glass rods, or on a combination of driven rollers and guides disposed between the spinneret and the collecting means. In more recent practice, however, the desired degree of a stretch has been imparted to the thread by means of a series of godet wheels operated at successively greater peripheral speeds. At least two and, where there have been only two, both of V such godet wheels have been positively driven at o angular speeds such as to produce the-desired a speed differential.

The difficulties encountered in such arrangements are well known to those familiar with the art. The employment of guides or glass rods 6} introduces a very high degree of friction resulting in broken filaments, nonuniformity of tensile strength, and inequality of denier. Godet wheels give rise to unsatisfactory results for the reason that the thread often tends to underwind, dam- 10 aging or snarling the filaments thereof; in addition, considerable slippage of the thread occurs, adverselyafiecting uniformity of denier, tensile strength and dyeing qualities. In either event, if, as is frequently the case, variations occur in 18 the degree of coagulation of the thread at the time 01 actual stretching, the drastic pull to which the thread is subjected during stretching tends to intensify the effect of the original irregularity.

The use of a generally flared thread store de- 5 vice, preferably the frusto-conical thread-advancing reel of the present invention, overcomes these difliculties.

From the principle of operation of such a device it is apparent that the friction exerted upon 10 the'thread is negligible. The underwinding and thread slippage characteristic of operation with godet wheels are virtually impossible. ,By increasing the diameter or-the length of the reel, any given length of thread from a very few feet 5 up to several hundred feet can be advanced at one time upon the periphery of one and the same reel; so that the same progressively increasing tension can be gradually applied to every sueceeding increment of the thread. The result is 20 a degree of uniformity in the physical and physico-chemical characteristics of the stretched thread heretofore quite unattainable.

Extensive experiments have established that on a reel of the hind shown the coagulation of the filaments approaches completion only after the lapse of a considerable time .nterval not usually less than twenty or thirty seconds, depending in part on the nature of the coagulating bath.

It has also been found that a progressively increasing tension exerted upon thread during most, if not all, of the timewhile coagulation of the filaments is still incomplete tends to enhance the desirable qualities which it is sought to develop in the thread. This is by way of contrast with the conventional spinning methods heretofore employed in which the stretching action, exerted over short lengths of thread not generally in excess of a few feet and for a duration of only one or two seconds, is invariably performed in the course of the early stages of the process of coagulation.

Whereas in ordinary practice the stretching does not in general exceed 20 to 30%, it is possible, depending upon the diameter and length of the reel used, to handle by the present invention lengths of thread well in excess of 100 feet. By

the application of the principles of the present invention the resultant stretch may easily be made double that employed in the older methods. At the same time, a product of much greater uniformity of denier, tensile strength and dyeing properties is made possible, this for the reason that no drasticpull .is applied to a relatively short length of thread, but instead a gradually increasing tension continuing over substantially the entire period of coaguuation.

As previously indicated, it is intended that the invention shall be understood as applying to the production of thread-like articles of synthetic w origin, not merely to multiple filament viscose artificial silk thread. The apparatus and method herein described represent but one embodimentof many possible embodiments of the invention. Various modifications within the scope of the appended claims may be made without in any way departing from the spirit of the invention.

It is intended that the patent shall cover, by" suitable expressionv in the appended claims, whatever features of patentable novelty reside in the invention. i

What is claimed is:

1. In the viscose process of manufacturing thead or the like, the method of stretching comprising the steps of forming the thread or the like by extruding viscose through a spinning noz.. 'zle into a coagulating bath; withdrawing the thread or the like from said coagulating bath be= fore the thread or the like has had an opportunity to attain a state approaching complete coagulation; gradually increasing the tension on the thread or the like while it is still in a state of incomplete coagulation by impressing upon it the form of a traveling helix characterized by a large number of closely spaced generally helicalturns of progressively increasing diameter, to t which is flared from a point near its receiving zone to a point near its discharge zone; and, after coagulation of the thread or the like has had an opportunity to proceed more nearly to comp-letion, passing the thread or the like to take-up means located in juxtaposition to said threadadvancing thread store device.

2. The method fof claim 1 in which, in the course of the stretching operation, a liquid is applied to the threador the like.

3. The method of claim 1 in which, in the course of the stretching operation, a reagent for furthering coagulation is applied to the thread or the like.

' HAYDEN Bi KLINE.

LOUIS S.- FRYER. 

